As for a mobile terminal that is not provided with a full keyboard such as a cell phone, a user generally uses a numeric keypad to input characters. For example, each row of Japanese is assigned to each key of numeric keyboard, such as row A to ‘1’, row KA to ‘2’, row SA to ‘3’ and row WA to ‘0’. The mobile terminal enables the user to input a desired character by displaying characters of each row in order (such as A→I→U→E→O→small A→small I→small U→small E→small O, KA→KI→KU→KE→KO, and the like) depending on the number of presses of each key. In the same manner, the mobile terminal enables the user to input the English alphabet by assigning characters to each key of the numeric keypad, such as a, b and c to ‘2’, d, e and f to ‘3’, g, h and i to ‘4’, and w, x, y and z to ‘9’. In addition, when the user keeps pressing each key for more than a predetermined period (long press), the characters assigned to the key are displayed in order as described above every predetermined period during long press of the key. Then by releasing the key (removes the long press) while the target character is displayed, the user can input the target character.
The same character input method is also applied to a mobile terminal provided with a touch panel as an input apparatus. In a numeric keypad displayed on a display screen, characters are assigned to a key displayed corresponding to an input position on the touch panel, and the characters assigned to the key are displayed in order depending on the number of inputs (presses) or duration of the long press to the input position (key). Thus, the input character can be determined by determination operation by the user.
In the case where a numeric keypad is configured by mechanical keys or buttons and the like (hard keys), when the method in which one of characters assigned to the key is determined depending on the number of presses is used, the user can perceive the target key based on the boundary or existence of convex and concave of keys by touching the keypad. Thus the user can input characters without watching the mobile terminal.
However, in the case of a touch panel, it is difficult to perceive the target input position (key) by touching. Therefore the user needs to determine the key position by watching it. Further, when the method in which the character assigned to the key is determined depending on the number of presses is used, in order to search the target character, the user needs to press the target key with watching it so that the characters assigned to the key are displayed one by one. Thus the user cannot input to the mobile terminal while doing other things that disturb the user in watching the mobile terminal, such as tapping keys for an e-mail while watching TV.
In order to avoid such inconvenience of input to a touch panel, an information input/display apparatus in which a touch panel is overlapped with a cover and convex and concave of the cover is changed has been suggested (see patent document 1). According to this patent document, the target position on a touch panel can be perceived by touching it.    Patent Document 1: Japanese Patent Application Laid-Open No. 9-319518